from queue import Queue
from threading import Thread


class Worker(Thread):
    """Thread executing tasks from a given tasks queue"""
    def __init__(self, tasks):
        Thread.__init__(self)
        self.tasks = tasks
        self.daemon = True
        self.start()

    def run(self):
        while True:
            func, args, kargs = self.tasks.get()
            try:
                func(*args, **kargs)
            except Exception as e:
                print(e)
            finally:
                self.tasks.task_done()


class ThreadPool:
    """Pool of threads consuming tasks from a queue"""
    def __init__(self, num_threads):
        self.tasks = Queue(num_threads)
        for _ in range(num_threads):
            Worker(self.tasks)

    def add_task(self, func, *args, **kargs):
        """Add a task to the queue"""
        self.tasks.put((func, args, kargs))

    def wait_completion(self):
        """Wait for completion of all the tasks in the queue"""
        self.tasks.join()

# if __name__ == '__main__':
#     from random import randrange
#     from time import sleep

#     delays = [randrange(1, 10) for i in range(100)]

#     def wait_delay(d):
#         print 'sleeping for (%d)sec' % d
#         sleep(d)

#     pool = ThreadPool(20)

#     for i, d in enumerate(delays):
#         pool.add_task(wait_delay, d)

#     pool.wait_completion()
